Boost C++ Libraries: Ticket #12402: knowing the current filename used by a boost.log text_file_backend

Andrey Semashev — Sat, 20 Aug 2016 00:43:38 GMT

There is no API to obtain the current file name. You could try implementing your own log file collector. Basically, the collector implemented in Boost.Log does not rename the file, it only moves it to the target directory, which you specify when you create the collector. So by implementing collector::store_file you should be able to know the full path to the last rotated log file. The currently written file name is inaccessible, you'll have to patch the library to change that.

Mon, 22 Aug 2016 13:57:35 GMT

I have modified text_file_backend so that it meets my requirements. I did this by:

adding to the open and close handler a string argument for the filename of the stream; the stream filename is readily available from m_pImpl->m_FileName where the open and close handlers are called by text_file_backend::consume and text_file_backend::close_file.
adding to the collector interface a set_store_handler callback method that the file_collector implements so it may use the callback in its implementation of the store_file method.

Right now I have put these changes in a copy of text_file_backend that I have incorporated into the source code of my local project. If you are interested, I can put these changes into a pull request for Boost.Log. As far as I can see, the changes are quite small and seem to fit in well with your text_file_backend implementation. Unfortunately, change (1), modifies the current text_file_backend open and close _handler_type types, so it will affect compatibility. I am not sure how, if at all, you want to deal with API changes.

I do, however, think the improved functionality my changes provide are important. Without these changes, I cannot meet either of my requirements. I would like to get this functionality into a future Boost.Log release as I do not like either choice of maintaining my own hacked copy of text_file_backend, or my own distribution of boost.

Thanks for all of your effort on Boost.Log!

status changed; resolution set

Andrey Semashev — Sun, 16 Oct 2016 14:55:17 GMT

status new → closed
resolution → fixed

Added a method to obtain the current log file name from the text file sink backend in https://github.com/boostorg/log/commit/a74e9d4a74dabe912f5eeeac3b7a987ad1c5b2e1.